MUSHROOM GROWING 



the late autumn and winter. Probably 

 under the most favorable conditions it 

 would prove necessary to make the beds 

 deeper than they are ordinarily made, and 

 to use some fresh manure at the bottom, so 

 as to maintain some degree of bottom heat. 

 Mulching w^ith clean straw is required, and 

 it is probable that cloth covers would be 

 desirable. The nature of the covers needed 

 would be determined by the daily range of 

 temperature. It is believed that there are 

 sections of California in which open-air cul- 

 ture might be profitably practised ; but there 

 is no available experimental evidence on a 

 scale worthy of consideration. It is of in- 

 terest to note that both Agaricus campestris 

 and A. arvensis are found in parts of Cali- 

 fornia during the winter months. The 

 mean monthly temperature of the city of 

 San Francisco and of an important section 

 of the State is normally from 50° to 60"" F., 

 and the daily range is not pronounced. 

 There is consequently a considerable terri- 

 tory thus favorably located as to tempera- 



42 



